There are more and more studies about how sleep affects our body and, especially, the brain. Now, research from the David Geffen School of Medicine at the University of Los Angeles, California (USA) and Tel Aviv University (Israel) confirms that lack of sleep has a severe impact on how the brain works, with potentially dangerous consequences in daily life. For the brain, not resting properly is like overdoing alcohol.
“We discovered that starving the brain also deprives neurons of the ability to function properly, which paves the way for the cognitive lapses of how we perceive and react to the world around us,” explains Itzhak Fried, leader of the work to the journal Nature Medicine.
The “inactive” neurons communicate inefficiently
The researchers worked with 12 people with epilepsy. All the participants had electrode implants in their brains, in order to record where their epileptic seizures originated in the period prior to surgery.
As part of their evaluation, the seizures were induced by insomnia, staying awake all night until they experienced an attack, so that electrical activity in the brain could be properly recorded.
In the experiment, participants received a categorization task in which they had to order different images in different categories as quickly as possible. While performing this task, the researchers focused on the electrical activity in the temporal lobe of the brain, which has been associated with memory and visual recognition.
The scientists observed that the more drowsy and tired the participants were, the harder the task was and the slower their execution.
“We were fascinated to see how sleep deprivation deadened the activity of brain cells,” says Yuval Nir, co-author of the work. Thus, with the lack of sleep, the brain cells became “slow” and neuronal communication was affected.
“The neurons responded slowly and their transmissions went on longer than usual,” says Nir.
The insomnia, therefore, caused that the activity of the brains – exhausted by the fatigue – was “drowsy”.
They also found that brain cells that took longer to respond were associated with slower brain waves, such as those normally recorded during sleep phases, and that this slow-motion activity was located in the same regions of the brain.
“The slow waves of sleep interrupted patients ‘brain activity and task performance, which suggests that the selected regions of the patients’ brains were dozing, causing mental lapses, while the rest of the brain was awake and functioning as as usual, “Fried says.
Researchers compare the lack of sleep with excessive drinking, and suggest that more appropriate measures should be taken against tired driving.
“Inadequate sleep exerts a similar influence on our brain to drink too much, but there are no legal or medical standards to identify tired drivers on the road in the same way that we attack drunk drivers,” the scientist concludes.